Many people who wind up buying timeshares will turn around one day and realize they don't want it anymore. This could be for any of a number of reasons; maybe they just need to raise a little cash, maybe they don't like the terms of the contract now that they understand them. At this point they may try to sell their second hand timeshare. This is where you swoop in and relieve them of what they don't want anymore while getting a quality piece of vacation property at a price that you just couldn't get on the firsthand market.
A lot of initial buyers of timeshares come to have buyers' remorse down the road. Why is this? As I states earlier, it could be for many reasons. For instance, after a couple visits, maybe they decide that they just don't like the place anymore. It doesn't mean that you won't like. Then they find out that they can't swap it for a time-share of a different property somewhere else. So what can they do? They can't sell it back to the company or developer they bought it from originally. They have no choice but to sell their second hand timeshare on the open market. They will have to sell it for a lot less than they originally bought it for, because these deeds depreciate pretty dramatically as soon as they are initially sold.
Another reason that people may try to sell their timeshare is because the maintenance fees have been hiked. I have heard of someone who had a timeshare in Mexico which got hit by a hurricane. Their fees jumped up to about $500 per month. So of course at that point many people would want to get rid of the property. But guess what? No one at all would buy it. No one would even take it for free. They ended up having to pay a company $2,000 to take this second hand timeshare off their hands!
Now that is an extreme example, but it does illustrate the wide spectrum of reasons and prices that timeshares may be sold on the second hand market. As long as you can do a little mathematical evaluation and read some "legalese", then you should be able to come up with your own valuation system for timeshares. Once you've got that down, then you can get to doing some online hunting for bargains in this great, new, and thriving resale market.